Tomato thrips
Frankliniella schultzei
Tomato thrips originate from South America and are widespread throughout Australia. They prefer to feed on flowers and have a wide range of hosts including tomatoes, tobacco, capsicums, lettuces, potatoes, grain legumes and several weed species. They are known vectors for tomato spotted wilt virus (TSWV) which can cause considerable yield losses in tomato, capsicum, potato and lettuce crops.
Description
Most prevalent in mid to late summer, tomato thrips range from dark brown to black, with clear wings and dark legs. They are slender and just visible to the eye (1.0-1.7 mm). Females lay eggs into flowers, leaves or fruit and the larvae hatch a few days later. Tomato thrips larvae are paler than adult thrips and are wingless. Early in the season thrips larvae are predominantly male but once numbers increase, females dominate the population.
While tomato thrips often reside in flowers, the sucking damage caused by both the larvae and adults produces deformed flowers, leaves, stems and fruit. In addition, shoots, fruit and leaves can develop a silvery appearance.
Control
Controlling volunteer host plants and weeds prior to planting and regular monitoring (particularly flowers) is essential to prevent tomato thrips populations from building. If required, insecticides are best applied before tomato thrips numbers peak. Several thrips species have developed insecticide resistance quickly, so rotating between different insecticide modes of action is important.Several natural predators feed on tomato thrips including pirate bugs, lacewing larvae and lady bird beetles so minimising the use of insecticides which reduce natural predators is recommended.
Tomato thrips hide in flowers which can be challenging to control with contact herbicides. Movento® is highly mobile within the plant, allowing hidden thrips to be controlled and it is also soft on many beneficial species when used as directed. Movento is registered for the control of tomato thrips in green beans, celery, rhubarb, herbs and bulb vegetables (excluding bulb onions).
References
Broughton, S, Jones, R and Coutts, B (2004) ‘Management of thrips and tomato spotted wilted virus’, Department of Agriculture WA, Farmnote 69/2004, https://ausveg.com.au/app/data/technical-insights/docs/fn069_2004.pdfPersley, D and Gambley, C (Viewed Oct 2019) ‘Plant viruses spread by thrips. Integrated virus disease management’, Queensland Government, DEEDI, (https://www.daf.qld.gov.au/__data/assets/pdf_file/0007/58777/Thrip-viruses-veg-crops.pdf
Rodoni, B and Henderson A (2010) ‘Tomato Spotted Wilted Virus in Potatoes’, Agriculture Victoria, Department of Environment and Primary Industries, http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/vegetable/potato-diseases/tomato-spotted-wilt-virus-in-potatoes
Steiner, M (Viewed Oct 2019) ‘Which thrips is that? A guide to key species transmitting Tomato Spotted Wilt Virus in NSW’, NSW Department of Primary Industries, https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/177324/tswv-transmitting-thrips.pdf